It has been found that in cultured Aplysia neurons bath applications of 40 mM cafffeine evokes oscillations of the membrane potential with about a 40 mV amplitude with a frequency of 0.2 to 0.5 Hz. The most probable mechanism of these caffeine-induced oscillations is inhibition of voltage-activated outward potassium current and, as can be seen from our mathematical modeling, slowdown of inactivation of inward sodium current. It seems likely that these oscillations have a purely membrane origin. Please see paper for results and details.
Reference: 1 .
Komendantov AO, Kononenko NI (2000) Caffeine-induced oscillations of the membrane potential in Aplysia Neurons. Neirofiziologiya/Neurophysiology32:102-111